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Lymphoscintigraphy
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Rimma Axelsson, Maria Holstensson, Ulrika Estenberg
The initial lymphatic vessels are composed of a porous basement membrane with a lining of loosely attached lymphatic endothelial cells. Such a structure permits easy drainage of fluid, macromolecules, colloids, cells, and cellular debris directly from extracellular space into the initial lymphatics. This fluid is called “lymph”. In the extremities, the lymphatic system consists of a superficial system that collects lymph from the skin and a deeper system that drains muscle and bone. In the legs these two systems merge within the pelvis, and in the arms, they merge in the axilla.
An introduction to skin and skin disease
Published in Rashmi Sarkar, Anupam Das, Sumit Sethi, Concise Dermatology, 2021
There are no blood vessels in the epidermis and the necessary oxygen and nutrients diffuse from the capillaries in the dermal papillae. These capillaries arise from horizontally arranged plexuses in the dermis. There are tiny arteriovenous shunts in the fingertips and other acral sites, which are referred to as glomus bodies. Their walls contain abundant plain muscle. The glomus bodies are specially designed for thermoregulation. The small lymphatic channels follow the blood capillaries but are distinguishable by the thin delicate lymphatic endothelium. Defective cutaneous vasculature is seen in Klippel–Trenaunay syndrome, Sturge–Weber syndrome, hereditary lymphedema, etc.
Pharmacological considerations for lymphatic malformation management
Published in Byung-Boong Lee, Peter Gloviczki, Francine Blei, Jovan N. Markovic, Vascular Malformations, 2019
Vascular endothelial growth factors (VEGFs) exert the major regulatory influence on lymphatic endothelial cell function and the process of lymphangiogenesis. In vitro investigation of the VEGFC/VEGFR3 signaling pathway in lymphatic endothelial cells has disclosed the fact that VEGFC induces activation of PI3K/Akt and MEK/Erk. The PIK3CA/AKT/mTOR and RAS/MAPK/MEK pathways interact and exert mutual regulation through cross-inhibition and cross-activation. The importance of PI3K in VEGF-C/VEGFR-3–mediated lymphangiogenesis provides a potential therapeutic target for lymphatic overgrowth and, coupled with additional vital in vivo human observations, has led to a new era of pharmacological intervention for such patients.
The Role of Inflammatory Cytokines in Neovascularization of Chemical Ocular Injury
Published in Ocular Immunology and Inflammation, 2022
Alireza Shahriary, Milad Sabzevari, Khosrow Jadidi, Farshad Yazdani, Hossein Aghamollaei
Corticosteroids are capable of controlling inflammation-induced angiogenesis in the early phase. But corticosteroids cannot reduce preexisting mature corneal neovascularization. In addition, the consumption of these drugs for a long-term burden superinfection, glaucoma, and cataract side effects.105 Although Subconjunctival Betamethasone treatment alone decreased VEGF-A secretion, it failed to regress corneal neovascularization induced by the chemical burn.106 Dexamethasone is another corticosteroid drug used widely in corneal angiogenesis. Dexamethasone partially blocks IL-1β-induced angiogenesis via arresting NF-κB signaling and VEFG-A production.31,107 Treatment of corticosteroids has demonstrated a drop in inflammatory corneal lymphangiogenesis. After 1 week the antilymphangiogenic activity of fluorometholone was slightly lower than that of prednisolone and dexamethasone in the injured mouse model. By the application of topical steroids, corneal macrophage recruitment was greatly impaired. Treatment of peritoneal exudate cells with corticosteroids has contributed to a major downregulation of TNF-α and IL-1β levels expression. Additionally, lymphatic endothelial cell proliferation was also prevented.108
Impairment of lymphatic endothelial barrier function by X-ray irradiation
Published in International Journal of Radiation Biology, 2019
S. Anand Narayanan, John Ford, David C. Zawieja
Understanding the response to radiation of lymphatic endothelium is critical in large part due to its investment in nearly every tissue in the body (in particular sites that are radiation sensitive such as the gastrointestinal system). This enhances lymphatic endothelium’s chances to be in a radiation field irrespective of site-directed or whole-body exposure. Furthermore, the lymphatic endothelium is critical for lymph formation and the transport of lymph from the lymphatic capillaries towards the lymphatic collecting vessels (Zawieja 2009). Lymphatic endothelial dysfunction consequently results in edema and inflammation. In the present study, we found significant increases in lymphatic endothelial monolayer permeability due to disruption of cell-to-cell adherens junctional protein structure and expression. Our study is the first to explore the effects of irradiation on the permeability of the lymphatic endothelium.
Study on enhanced lymphatic tracing of isosulfan blue injection by influence of osmotic pressure on lymphatic exposure
Published in Drug Development and Industrial Pharmacy, 2018
Tiantian Ye, Rui He, Yue Wu, Lei Shang, Shujun Wang
Lymphatic system is consisting of five main categories of conduits: the capillaries, collecting vessels, lymph nodes, trunks, and ducts. Lymph forms when interstitial fluid moves into the lymphatic capillaries [13]. Lymphatic capillaries are also called initial or terminal lymphatics, and are generally thought to be blind-ended structures and comprised of one endothelial cell layer which is highly attenuated in cross section. These unattached borders of the lymphatic endothelial cells may function as ‘microvalves’ or ‘inlet valves’ to the lymphatic lumen. Therefore, ‘valves’ may be opened during expansion of the initial lymphatics by means of a positive fluid pressure drop from the interstitium to the lumen. This suggested that when the pressure of the interstitial fluid exceeds that of the capillaries, the endothelial cell junctions are opened thus allows the transport of fluid into the lymphatic capillaries [13–15]. In conclusion, osmotic pressure is an important factor in lymphatic drainage, and, therefore, is closely related to the tracer effect of lymph tracer. Previous research shows that the osmotic pressure could enhance lymphatic drainage from the injection site and uptake into lymph node [16].